Single-end clearance unloader



I I 1 616,990 F 1927' s. B. REDFIELD SINGLE END CLEARANCE UNLOADER Filed Aug. 44 1926 INVENTOR. 62zouraZe2z Ellezffieial H16: AT RNEY 'ID The clearance valve Patented Feb. 8, 1921.

UNITED STATES'PATENT ounce.

SNOWDEN :B. REDEIELD, or EAs'ron; PENNSYLVANIA, ,ASSIGNGB/TO INGERSOLL-RAND comm, or .rEns Y crrx, NEW JERSEY, A coaronarrou or NEW JERSEY.

SINGLE-END CLEARANCE UNLOADE R.

. Application filed August 4,1926. Serial No. 127,004..

This inventionrelates to compressors, but

more particularly to a clearance unloader this means the desired numberof steps may be obtained in a simple manner.

The invention is shown in one suitable form in the accompanying drawmg m which r The figure is a diagrammatic representation of a single end clearance unloader partly in longitudinal sectional elevation.

Referring to the. drawings, the cylinder A is provided with a iston- B and air drawn in at the intake C is discharged through the discharge outlet D to the receiver E.

The cylinder is provided with the'usual inlet anddischarge valves F and G of any suitable type as for instance plate valves. A

dividedclearance'chamber H is located in any suitable position on the cylinder and provided with a clearance valve J at one end of the cylinder. An auxiliary valve K controls communication between the divisions of the clearance chamber. One inlet valve L at the end of the cylinder opposite the clearance valve J is provided with a suitable valve opener and the clearance valve J and auxiliary valve- K are each provided 7 with means for opening the valves. A. suitable regulator O responsive to receiver pressure through the pipe P controls the clearance valve J, the auxiliary valve K and the valve opener of the inlet valve L for producing step by step clearance control.

The first step of unloading consists inopening the clearance valve J whi'h unll loads the compressor one quarter. This valve is then maintained opened and the auxiliary valve K is opened which doubles the capacity of the clearance chamberand produces half load.

J is maintained opened for the third step but the auxiliary 'valve K is closed and t e inlet valve L at the opposite end oithecylinder from the clearance valve J is opened producing one I quarter load. In the final step the clearance will rapidly close due tov lea valve J andthe inlet valve L are maintained opened and the auxiliar valve K is'reopened to wholly unloa These steps are repeated in reverse order when the compressor is reloaded.

The clearance valve J is provided with the piston Q, in the cylinder R and pressure fluid is supplied beneath the piston through the pipe 1 to open the valve J and maintain lt'open until returned by the spring S. The auxilia valve'K is provided with thepiston- Q, in the cylinder T and is supplied with pressure beneath the piston throu h the pipe 2., After the valve K is opene and pressure is cut off from the pipe 2, the valve age of pressure the compressor.

through the vent U which is of suflicient' size to permit this 0 eration. .The inlet valve L- has the piston in the cylinder W and'fingers X connected to the piston rod are adapted to bear on the valve and open the valve when pressure is supplied to the' cylinder through the ipe 3. A spring Y normally retracts the gers. Y

The pipes 1, 2, and 3 lead respectively to the ports a, b and 0- in the cylinder of the regulator Q, a fourth port at also'connec'ts with the pipe 3. The regulator is provided with the piston ehaving the ports f, g, h

and j connected by the passage In with that I end of the cylinder to which pressure is introduced. The opposite end'of the cylinder .is vented at 0 and an adjustable spring p retracts the piston e.-

. In the operation of the ap aratus, assum ing that the compressor is oaded as indicated in Figure'l, the first stepof unloading is effected when the port registers with the port a so that pressure uid is supplied to the cylinder R of the clearance valve. J to open said valve and unload the compressor one quarter producing three quarters load. In the next step of unloading the ports f and g .register respectively with-the ports I) and a so that the clearance valve J is maintained open and the auxiliary valve K is open to double the capacit of the clearance chamber and produce ha f load. In the next step of unloading the ports f and h register with the ports a and a respectively one: quarter load or three quarters unloading.

unloa ed.

, clearance valve, the auxiliary I claim: 1. In a compressor unloader,- the -COI l1l)1- nation of a cylinder and piston, inlet anddischarge valves, ,a receiver, a divided clear ance chamber for one end of the cylinder, an auxiliary valve between the dlVlSlOIlS of said chamber, a clearance valve for saidchamber opening into one end of the cylinder, an inlet valve opener for an inlet valve at the, op osite end of the cylinder, and pressure fl iiid means for controlling said valve, and the inlet valve opener.

- 2. In a compressor unloader, the combination-of a cylinder and piston, inlet discharge valves, a receiver, a divided clearance chamber for one'end of the cylinder, an auxiliary valve between the divisions of said chamber, a clearance valve :for said chamber opening into one end of thecyhnder, an inlet valve opener for an inlet valve atthe opposite end of-the cylinder, and a regulator responsive to receiver pressure for controlling said clearance valve, the auxiliary valve andthe-inlet valve opener in predetermined order for step by step unloading.

3. In a coin ressor unloader, the combination of a cy inder' and piston, inlet and discharge valves, a receiver, a divided clearance chamber for one end of thevcylinder, an auxiliary valve'between the divisions of said chamber, a clearance valve for said chamber opening into one end of the cylinder, an inlet valve opener for an inlet valve at the opposite end of the cylinder, and automaticmea'ns for first openin the clearance valve, then opening the auxiliary valve,

then closing the auxiliary valve and opening said inlet valve by means of said inlet valve opener while maintaining the clearance valve open, and finally reopening the auxiliaryvalve while maintaining {boththe clearance valve and the said inlet valve open.

In testimony whereof I have signed this specificatioii.

SNOWDEN B. REDFIE'LD. 

